1. Field of the Invention
The present invention relates to a technology for controlling an electric equipment. More particularly, the present invention relates to a technology for controlling an electric equipment using power line communication.
2. Description of Related Art
In a conventional lamp control system, a same lamp source can be controlled with a plurality of switches at different positions. For example, in a corridor, the control switches of a same lamp source can be arranged at both ends of the corridor. Thus, a person walking through the corridor can turn on the lamp source with the switch when steps into the corridor, and turn off the lamp source with the switch at the other end, thereby saving the power.
FIG. 1 is a circuit diagram of a conventional lamp control system. Referring to FIG. 1, a plurality of switches, e.g., S1 and S2, are included in the conventional lamp control system 100, for controlling the turn on/off of a lamp source L. The switches S1 and S2 are connected in series. When the switches S1 and S2 assume positions 1 and 4 respectively, or at positions 2 and 3 respectively, the lamp control system 100 is in an open-circuit state, so the lamp source L is turned off.
In an initial state, the switches S1 and S2 assume positions 1 and 4 respectively. When a user switches the switch S1 from position 1 to position 2, or switches the switch S2 from position 4 to position 3, the lamp control system 100 forms a loop with a power source AC1, such that the lamp source L emits light. After the user switches the position of the switch S1 or S2 to turn on the lamp source L, the user can switch the position of any one of the switch S1 or S2 again to turn off the lamp source L.
Though the circuit diagram of the lamp control system 100 of FIG. 1 is quite simple, in practice, the circuit is very complicated. FIG. 2 is a schematic view of actual wiring of a conventional lamp control system. It is known from FIG. 2 that the wiring of the conventional lamp control system 100 is very complicated. Moreover, when the number of switches increases, the complexity of wiring will increase in multiples. In addition, in the conventional lamp control system 100, after the switches S1 and S2 are configured, new switches cannot be added. In order to add new switches, the wirings of the entire lamp control system 100 must be completely removed, and new pipelines must be arranged to add a set of switches, which is very uneconomical.